Fig. 2. dsRNA and ERV levels increase after irradiation.

a Immunofluorescence staining for K1 antibody indicating dsRNA, indicative of residual DSBs in A549 cells. Scale bars: 20 and 2 µm for the magnified images. b Quantification of dsRNA at 3 h after irradiation. Positive areas and signal intensities were automatically calculated using a hybrid cell count application (BZ-H4C, KEYENCE). Data were presented as the mean ± SEM of three biological replicates. *p ≤ 0.01, paired t-test. c Fold change in LTR expression between irradiated (IR) and nonirradiated (NIR) A549 cells. The IR group was harvested 7 days after 8 Gy irradiation, and the NIR group was harvested at the same time without irradiation. The expression of LTRs was quantified by total RNA-seq. Data were inclusive of two independent experiments. The red dots indicate the LTRs with a more than a twofold change in abundance in IR cells compared with NIR cells. d Immune-related LTR expression levels in the NIR group and in the IR group at 4 and 7 days post-irradiation. e Protein levels of RIG-I and representative markers of immune activation.